Build: Create script to set the version on MapGuide source files pre-build

Description

With automated builds, we will want a way of distinguishing which version of the application a user is running by inspecting any of the various version properties (dlls, server version number, etc, etc).

On the -internals list, we agreed to do this by using a fixed Major.Minor.Point, and then basing .Build on the SVN revision mod 32767. E.g.: 2.1.0.3802

This needs to be done in an automated manner so that the build system can do this without manual intervention.